Clathrin-coated vesicles (CCVs) carry out receptor-mediated endocytosis at the plasma membrane, where they mediate the uptake of receptor bound nutrients, hormones and proteins destined for degradation. In the trans-Golgi network, CCVs are required biogenesis of lysosomes and secretory granules. The assembling unit, or clathrin triskelion, is composed of three heavy chains and three light chains. The polymerization of clathrin triskelions drives the formation of the lattice: thus clathrin self-assembly provides the mechanism for the receptor-concentrating function of clathrin-coated vesicles, leading to selective transport of any elements that can associate with the lattice. The structural analysis of the recombinant hub/LCb complex will lead to the molecular mechanism of clathrin self-assembly.